雨课堂学堂在线学堂云Experiments in Biochemistry（生物化学实验）(南京大学)单元测试考核答案

第1题Whichwavelength(nm)isusedinthecolorimetricassay?(

)A380B450C620D560第2题Theconcentrationofsulfuricacidusedtopreparetheanthronereagentis(

).A25%B98%C80%D50%第3题Thestandardcarbohydratesolutionusedinthisexperimentis().A1.0mg/mLglucosesolutionB0.1mg/mLglucosesolutionC0.1mg/mLsucrosesolutionD1.0mg/mLsucrosesolution第4题Thisexperimentisusedtodeterminethe()contentinplants.AtotalsolublecarbohydrateBsolublereducingcarbohydrateCtotalcarbohydrateDcellulose第5题Anthronecolorimetricassaycouldbeusedtodeterminewhichofthefollowingsubstances?(

)AmonosaccharideBstarchCfructoseDglycogen正确答案：ABCD第6题Beforeaddingtheanthronereagent,thetesttubeshouldbecooledinanicewaterbath.()第7题Differentcarbohydratesreactwithanthronereagents,exhibitingdifferentcolordarkness.()第8题Whenthecarbohydratesamplecontainsproteins,itcanbedirectlymeasuredwithoutremovingtheproteinsinadvance.()第9题Carbohydrateisdehydratedbytheconcentratedsulfuricacidtoproducefurfuralorhydroxymethylfurfural.Furfuralorhydroxymethylfurfuralcanreactwith____toproducesomeblue-greenfurfuralderivatives.正确答案：:Anthrone第10题Afteraddingtheanthronereagent,solventsneedtobeaccuratelyheatedinaboilingwaterbathfor____minutestocompletethereaction.正确答案：:10第1题TheroleofI2-KIsolutionis().AIndicatingwhethertheextractiscompletelyhydrolyzed.Thesolutionturnsblueifhydrolysisiscompleted.BIndicatingthattheextractcontainsamylopectin,anditturnsblueifstarchcontaining.CIndicatingwhethertheextractiscompletelyhydrolyzed.Thecompletedhydrolysissolutiondoesnotturnblue.DIndicatingwhetherthepHvalueisacidic.第2题Whichofthefollowingstatementsaboutthisexperimentarecorrect?()AReducingcarbohydrateisreductiveandcontainfreealdehydegroupsorketonegroups.BTotalcarbohydrateincludesreducingcarbohydrateandnon-reducingcarbohydrate.CWhendeterminingthetotalcarbohydrateinthisexperiment,itisnecessarytofirstlyhydrolyzethetotalcarbohydratetoreducingcarbohydrateunderacidicconditions.DItisnecessarytoconstructastandardcurveusingseveralconcentrationsofstarchsolution.正确答案：ABC第3题Whenextractingthetotalcarbohydrateofthesample,treatmentwithconcentratedHClisintendedtocompletelyhydrolyzethetotalcarbohydrateintomonosaccharides.NeutralizationtheHClwithNaOHbeforemeasurementisintendedtokeepthealkalineenvironmentof3,5-dinitrosalicylicacidreagentaswellastheprogressionofthereaction.()第4题AfteraddingDNSreagenttothesample,thetimeoftheboilingwaterbathdoesnotneedtobestrictlycontrolled.()第5题Theadditionofcrystallinephenoltothe3,5-dinitrosalicylicacidreagentisintendedtoenhancethecolor-reactionefficiencyofthereagent.()第6题Additionofsodiumsulfitetothe3,5-dinitrosalicylicacidreagentcouldeliminatetheinfluenceofdissolvedoxygeninthereagentandstabilizethereagent.()第7题____:Aseriesofcomplicatedreactionsbetweenreducingcarbohydrateandaminoacids/proteinswhenheated.Itwillproducebrownorblackmacromolecularsubstances,andintermediatemoleculeswithdifferentodors,includingreducingketones,aldehydesandcycliccompounds,providingattractiveflavorandcolorforfood.正确答案：:Maillardreaction第8题Inconstructingthestandardcurveofreducingcarbohydrate,DNSreagent____beaddedtotheblanktube(fillin"should"or"shouldnot")正确答案：:should第9题Whenmeasuringthecontentofreducingcarbohydrateby3,5-dinitrosalicylicacidmethod,thewavelengthis____nm.正确答案：:5407.Homework第1题Thestandardofconstantweightintheexperimentisthatthedifferencebetweenthetwoweightsdoesnotexceed()mg.A0.2B1C2D5第2题TheSoxhletextractionusedinthisexperimentisbasedon(

).Aweight-lossmethodBgravimetricanalysismethodCresiduemethodDimmersionmethod第3题Whichfollowingsubstancescannotbeusedaslipidextractionsolvents(

).AetherBpetroleumetherCethylacetateDwater第4题Whichofthefollowingsubstancesbelongtocrudefat?(

)AfreefattyacidBphospholipidCcelluloseDsterol正确答案：ABD第5题Inthisexperiment,thecrudelipidsareextractedwithpetroleumether.Ifthetemperatureisnotenoughhigh,analcohollampcanbeused.()第6题Afterextraction,thesmallflaskcontainingthecrudelipidssampleisdriedat103-105°Cfor30min.Becarefulnottooverheat.()第7题Onlywhentheheightoftheliquidlevelintheextractionchamberishigherthanofvaportube,thesolutionintheextractionchambercouldflowbacktothesmallflaskthroughthesiphonarm.()第8题Beforeextraction,thefilterpaperbagcontainingthesampleshouldbeplacedinthe____.正确答案：:Extractionchamber第9题Soxhletextractorisarefluxdevice,whichiscomposedofasmallflask,____andacondenser.正确答案：:Extractionchamber第10题Theheatinginstrumentusedfortheextractionofcrudelipidsis____.正确答案：:thermostatwaterbath7.Homework第1题TheAcidValueismeasuredbythemilligramsofpotassiumhydroxideneededtoneutralizethefattyacidsin100goflipids.()第2题WhenKOHisreplacedwithNaOHatthesameconcentrationasthetitrationalkaline,onlythemolecularweightofKOHneedstobereplacedwiththemolecularweightofNaOHincalculatingtheacidvalue.(

)第3题Dissolvelipidsinthealcohol/ethermixturewhichistitratedinadvance.How

willthesolventcolorchange?Whichoneisthecorrectexplanationofthecolorchange?(

).AThesolutionchangesfrompaleredtocolorless.Becausethefattyacidsinthelipidsmakethesolutionacidic.BThesolutionchangesfromcolorlesstopalered.Becausethefattyacidsinthelipidsmakethesolutionacidic.CThesolutionchangesfromcolorlesstopalered.Becausethefattyacidsinthelipidsreactwithalcohol-ether.DThesolutionchangesfrompaleredtocolorless.Becausethelipidsreactwithindicatorreagent.第4题Hydrolysisoflipidsreleasesfreefattyacids,whichwillbeoxidizedtoproducealdehydesorketonesintheair,creatingsome

bad

smell.Thisphenomenoniscalled

____oflipid.正确答案：:Rancidity第5题Thetitrationiscompletedasthesolutionturns(

).APalered,maintainingwithoutfadingBDarkred,maintainingwithoutfadingCPalered,maintainingfor1minutewithoutfadingDDarkred,maintainingfor1minutewithoutfading第6题Inordertodeductthebackground,thealcohol-ethermixtureis

usedtodissolvethelipids

needstobetitratedinadvance.(

)第7题Whichofthefollowingindicatorsareusedtomeasurethefreshnessoflipid?(

)AIodinevalueBAcidvalueCPeroxidevalueDMalonaldehydevalue正确答案：BCD第8题Which

of

thefollowingstatementaboutacidvalueiscorrect(

).AThelowertheacidvalue,thelessoffreefattyacidscontent,andthebetterofthelipidquality.BThelower

theacidvalue,themoreoffreefattyacidscontent,andthebetterofthelipidquality.CThelowertheacidvalue,thelessoffreefattyacidscontent,andthepoorerofthelipidquality.DThelowertheacidvalue,themoreoffreefattyacidscontent,andthepoorerofthelipidquality.第9题Acidvalueisoneofthestandardstomeasurethecontentof____infat.正确答案：:Freefattyacids7.Homework第1题What

isthegeneralproceduretodeterminetheN-terminalaminoacidofaproteinorpeptidebyDansylmethod(

).ADNSmodification→

Acidhydrolysis→

SeparationandidentificationbychromatographyBAcidhydrolysis→

DNSmodification→

SeparationandidentificationbychromatographyCAcidhydrolysis→

Separationbychromatography→

DNSmodificationandidentificationDDNSmodification→

Separationandidentificationbychromatography第2题Accordingtotheresultsofthisexperiment,DNS-Gly(A)andDNS-Leu(B)willmigrate

inthemobilephasesolutionI(benzene-glacialaceticacidsolution).Theonewiththehighestmigrationvelocityis____(fillin"A"or"B").正确答案：:B第3题Theretardationfactor

Rf

ofthesampleistheratioofthedistancefromtheloading

spottothechromatographyspot

____andthedistancefromtheloading

spottothesolventfront.正确答案：:center第4题Whenloading,thespotdiametershouldbecontrolledwithin2mmandthefilmisdriedwithhotwind.(

)第5题WhichofthefollowingaminoacidswillproducemorethanoneDNS-modifiedproducts?

()ALysBHisCTyrDLeu正确答案：ABC第6题We

can

observethechromatographicresultsunder____.Notethattheobservationtimeshouldnotbetoolonginordertoprotectyoureyes.正确答案：:UltravioletLamp第7题DNS-OHisaby-productofthis

reactionandcould

bedistinguishedfromDNS-aminoacidsby

itsbluefluorescence.(

)第8题Chromatographyisaseparationmethodbasedonthedistributioncoefficientdifferenceofcomponentsinthemixturebetweenthestationaryphaseandmobilephase.Thegreaterthedifferenceofdistributioncoefficientthebettertheseparationefficiency.第9题Inthisexperiment,whichof

thefollowingstatementsarecorrect().AAfterthepreparationofDNS-ClsolutionwithaminoacidsandpHadjustment,themixtureisincubatedtoreactin40°Cwaterbathfor2hoursindark.BTakeapieceofpolyamidefilmwithitsobversesideupward.Drawanintersectionlinewithapencilat1.0cmawayfromeachedge.Intersectionoftwolinesistheloadingspot.CAfterloading,curlthepolyamidefilmwithpolyamidesideoutward.Avoidcontactofbothsidesandthentiethefilmrollwithrubberbands.DNotethattheheightofthemobilephaseishigherthanthatofthespottingpoint.正确答案：AC第10题WhenpreparingDNS-aminoacid,whichoneofthepHrangesis

required?A5.5-7.5B6.0-9.0C7.5-9.5D9.0-10.5第11题DNS-aminoacidscanemit()fluorescenceunderultravioletlight.ALightblueBBlue-greenCYellow-greenDLightpink7.Homework第1题Whichofthe

followingstatementiswrong(

).AResinisinertinsolublepolymer.BThefunctionalgroupofthecationexchangeresinisacidic.CThefunctionalgroupoftheanionexchangeresinisalkaline.DThedissociableOH-ofthecationexchangeresincould

exchangewithcationsinthesolutionphase.第2题Bypretreatmentof

freshresin,theimpurities,suchasresidualsolvents,oligomersandafewheavymetalions(suchasFe3+,Cu2+),could

beremoved(

)第3题Pre-equilibrateisrequiredafterpacking.(

)第4题Besidesionexchangecolumnchromatography,otherchromatographytechniquesinclude(

).AHydrophobicchromatography:Substanceshavedifferentaffinitiestothehydrophobicgroupscoupledwiththeresin.BAffinitychromatography:Substancesbindtothespecificgroupsoftheresinwithdifferentaffinities.CGelfiltrationchromatography:Itisbasedonthemolecularweightdifferenceofseparatedcomponents.DIsoelectricFocusing:The

differenceinisoelectricpointamong

theseparatedsubstances.Itisbasedontheisoelectricpointdifferenceofseparatedcomponents.正确答案：ABCD第5题Which

of

thefollowingstatementis

correct?(

)AWhentheisoelectricpointpI<pH,theproteinispositivelychargedandcanbindwiththecationexchangeresin.BWhentheisoelectricpointpI<pH,theproteinisnegativelychargedandcannotbindwiththecationexchangeresin.CWhentheisoelectricpointpI>pH,theproteinispositivelychargedandcanbindwiththecationexchangeresin.DWhentheisoelectricpointpI>pH,theproteinisnegativelychargedandcannotcombinewiththecationexchangeresin.正确答案：BC第6题Whichofthefollowingmethodisbasedonthechargedifferencecarried

by

the

chargedmoleculestoseparatediversesubstances?(

)AHydrophobicchromatographyBAffinitychromatographyCIonexchangechromatographyDGelfiltrationchromatography第7题Theresinshouldbeaddedintothecolumn____(fillin“slowly”or“quickly”)toavoidproducingairbubbles.正确答案：:slowly第8题Accordingtothedifferentnumbers

ofaminoandcarboxylgroupscontainedinaminoacids,aminoacidsaredividedintothreecategories:acidicaminoacids,____aminoacidsandbasicaminoacids.正确答案：:neutral7.Homework第1题InordertoobtainanaccuratepH,itisbesttouseapH

meterformeasurement.(

)第2题Beforeprecipitating,bothmilkandacetate-sodiumacetatebuffershouldbepre-incubated

inawaterbathat____℃

forawhile.正确答案：:40第3题WhenthepHofthesolutionisequal

to

theisoelectricpointoftheprotein,thesolubilityoftheproteinisthe____(fillin"highest"or"lowest")正确答案：:lowest第4题Inthisexperiment,concentratedhydrochloricacidcould

beusedinsteadofglacialaceticacidtoadjustpH.(

)第5题Caseiniswhiteandodorless.Itisinsolubleinwater

andorganicsolventssuchasethanol,butsolubleinalkalinesolutions.(

)第6题Inthepresentexperiment,whatisthepossiblereasonthat

leads

to

thecontentofthecaseinhigherthanthetheoreticaloractualvalue?()AThe

pHadjustedbyglacialaceticacidreachesto3.BSomewheyproteinswillprecipitateduringtheheating

process.CThemilkgoesbad.DRinsingisincompleteandcausesotherimpuritiesinproteinsample.正确答案：BD第7题Regardingthepreparationofcaseininmilk,which

of

thefollowingstatementis

correct().ACaseinisthemostabundantproteininmilkBGlacialaceticacidisusedtoadjustthepHofmilk.ProteinwillprecipitateifthepHofthesolventisnearitsisoelectricpoint.CSomewheyproteinswillalsoprecipitateoutwhileheated.DInthepurificationofcasein,differentrinsingsolventsisusedinsequence.正确答案：BCD第8题Theisoelectricpointofcaseinis(

).A3.0B4.7C7.0D7.6第9题Themost

abundantproteininmilkis(

).AWheyproteiBAlbuminCCaseinDGlobulin7.Homework第1题Whichofthefollowingmethoddoesnotconsumeproteinsamples,andtheproteincanstillberecycled

aftermeasurement(

).ABiuretmethodBUltravioletabsorptionmethodCFolin-phenolreagentmethod(Lowrymethod)DKjeldahlmethodECoomassieBrilliantBluemethod第2题Thedetectionwavelengthis

at

____nminCoomassieBrilliantBluemethodfordeterminationofproteinconcentration.正确答案：:595第3题Ultravioletabsorptionmethod

canbeusedtoidentifythepurityofprotein.Whenthecontent

of

nucleicacidinthesampleincreases,thevalueofA280nm/A260nmwill____(fillin"increase"or"decrease")正确答案：:decrease第4题WhenusingCoomassieBrilliantBluemethodtomeasureproteins,whichofthefollowingfactorswillinterferewiththeresults?(

)APotassiumionsBMagnesiumionsCEthanolDTritonX-100第5题WhenusingtheCoomassiebrilliantbluemethodtodetermineprotein,theproteincontentofthesampleshouldbe10-100µg.(

)第6题Whenusingultravioletabsorptionmethodtodetermineproteinsamples,quartzcuvetteshouldbeusedinsteadofglasscuvette.(

)第7题Whatfactorsshouldbeconsideredinthemethodsselectionofproteinconcentrationdetermination?(

)AThepropertiesoftheanalyzedproteinBThesensitivityandaccuracyrequiredintheexperimentCInterferingsubstancespresentinthesolutionDThetimeittakestodeterminetheproteinconcentration正确答案：ABCD第8题Which

istheinternationalstandardmethodfordeterminationofproteincontent?(

)ABiuretmethodBUltravioletabsorptionmethodCCoomassieBrilliantBluemethodDKjeldahlmethod第9题Whichoffollowingaminoacidshaveconjugateddoublebonds?(

)ATyrosineBTryptophanCAlanineDPhenylalanine正确答案：ABD第10题Besides

CoomassieBrilliantBluemethod,()methodscan

alsobe

used

to

determineproteinsconcentration.AKjeldahlmethodBBiuretmethodCFolin-phenolreagentmethod(Lowrymethod)DUltravioletabsorptionmethod正确答案：ABCD7.Homework第1题Aftertheproteinbandisleachedbytheleachingsolution,itisquantifiedbycolorimetricmethod

at____nm.正确答案：:590第2题Thesample

shouldbeloaded

onthecelluloseacetatemembrane____theshinyside(filledwith"with"or"without").正确答案：:without第3题Thestainingreagentusedinthisexperimentis(

).ACoomassieBrilliantBlueG250solutionBCoomassieBrilliantBlueR250solutionCAminoBlack10BsolutionDPonceauSsolution第4题Whichofthefollowingoperations

are

correctinserumproteinsseparationby

celluloseacetatemembraneelectrophoresis?

(

)ABeforeloading,spongeuptheexcesselectrophoresisbufferonthesurfaceofthefilmwithfilterpaper.BSomeserumsampleisdippedwiththecross-sectionofaspottingslideandgenerallykeeptheslide-filmcontactingfor2to3secondsduringloading,untiltheserumpenetratesthemembrane.CThewidthoftheloading

isshorter

thanthatofthemembrane,avoidloading

repeatedly.DToomuchloading

willresultinunclearbandboundaries.正确答案：ABCD第5题Inthisexperiment,theproteins

innormalhumanserumareseparatedandmigratedinto5bands.Thesequencefromanodetocathodeis:____,α1-globulin,α2-globulin,β-globulinandγ-globulin.正确答案：:Albumin第6题Theresultofnormalhumanserumbycelluloseacetatemembraneelectrophoresisisshownasfollows.Thepossiblereasonoftheunsatisfactoryseparationis(

)Atheloading

volumeistoolargeBloading

repeatedlyCtheloading

widthistoolargeDtheelectrophoresistimeistooshort第7题TheisoelectricpointofimmunoglobulininserumismostlyaroundpH7.Forexample,pIofIgMis7.0andpIofIgAis7.4.AftercelluloseacetatemembraneelectrophoresisusingpH8.6barbituratesodiumelectrodebuffer,whichregionwillthesetwoproteinslocateat?(

)AnearAlbuminBnearα1-globulinCnearα2-globulinDnearβ-globulinEnearγ-globulin正确答案：E第8题ThepHoftheelectrodebuffercommonlyusedtoseparateserumproteinsbycelluloseacetatemembraneelectrophoresisis(

).A4.8B5.8C6.8D8.6第9题Proteinsseparatedbycelluloseacetatemembraneelectrophoresisarequantifiedaccordingtothewidthofeachbandafterelectrophoresis.(

)第10题Theproteinsampleseparatedbycelluloseacetatemembraneelectrophoresiscanberecycledandreused.(

)第11题Celluloseacetatemembraneelectrophoresishaslowerresolutionthanpolyacrylamidegelelectrophoresis(PAGE)in

proteinsseparation.(

)7.Homework第1题InSDS,thegreatertherelativemolecularmassoftheprotein,the____therelativemigrationratewillbe.

(Fillin"faster"or"slower").正确答案：:slower第2题SDSgelisdividedintoupperandlowerparts,thelowerpartiscalled____.正确答案：:separatinggel第3题In

SDS,reducingsubstancesareusedtobreakdisulfidebonds.Therefore,themolecularweightsofthesubunitsorsinglechainswill

be

actuallymeasured.(

)第4题InSDS,proteinsmovefromanodetocathode.(

)第5题InSDS,themigrationrateofproteinsonlydependsonthemoleculesizeandhasnothingtodowiththechargeandmoleculeshape.(

)第6题Thesampleshouldbeboiledfor10minutesbeforeloading.(

)第7题TheroleofSDSinthisexperimentis(

).APrecipitateproteinBBindwithproteinmoleculesinacertainproportionCLettheproteinscarrylargeamountofnegativechargestoeliminatetheoriginalchargedifferenceDFullydepolymerizeproteinsintomonomers正确答案：BC第8题Afteraddingtheseparatinggelsolutionintothegapbetweentwoglassplates,itisnecessarytocovertheseparatinggel

withalayerofwaterimmediately.Thepurposeofthisoperationis(

).Aeliminating

bubblesBpreventing

oxygenfromdiffusingintothegelandinterferingwithpolymerizationCdiluting

thegelDspeeding

upthegelpolymerization正确答案：AB第9题Ingeneral,theconcentrationofstackinggelindiscontinuousSDS

is(

).A5%B8%C12%D10%第10题ThepHofSDSelectrophoresisbufferis(

).A8.3B8.8C6.8D7.07.Homework第1题DNA-binding

proteins

(DNP)existsinthenucleusandisslightlysolubleinhighsaltsolution(1mol/L)andsolubleinlowsaltsolution(0.14mol/L).()第2题Incells,DNAorRNAareusuallyprotein-binding.(

)第3题SDScan

removethe____boundwith

DNAduringtheDNAextractionprocedure.正确答案：:proteins第4题DuringDNAextraction,chloroform-isoamylalcoholandSDSareadded.Aftercentrifugation,thelayers

areshows

inthe

figure.Which

of

thefollowingstatementsarecorrect?(

)ATheupperlayerisanaqueousphasecontainingDNA,themiddlelayerisdenaturedproteins,andthelowerlayerischloroform.BTheupperlayerischloroform,themiddlelayerisdenaturedprotein,andthelowerlayerisanaqueousphasecontainingDNACSDScandestroytheadvancestructureofproteinsandcausetheproteinstodissociatefromDNA.DChloroformisaproteinsdenaturant,whichcanprecipitateproteinandacceleratetheseparationoforganicphaseandaqueousphase.正确答案：ACD第5题RegardingtheextractionstepsofanimalliverDNA,which

of

thefollowingstatementsarecorrect?(

)ALargepiecesoflivertissuecould

bedirectlyhomogenized.BWhentheglassrodiswrappedaroundwithDNA,itshouldbestirredquicklyinthesamedirection.CDNAextractionprocessshouldavoidexcessiveacid,alkali,hightemperatureanddamageby

mechanicaltension.DNaClpowdershouldbeaddedinbatchesandshakenasitisaddedtoavoidhighlocalsaltconcentration.正确答案：CD第6题ToquantifyDNAwiththediphenylaminecolorimetricmethod,theabsorbance

value

shouldbemeasuredat____nm.正确答案：:595第7题WhenextractingliverDNA,whichofthefollowingconcentrationofsaltsolutioncoulddissolveDNAthebest?(

)A0.05mol/LB0.5mol/LC1mol/LD10mol/L第8题DNAreacts

withdiphenylaminereagentinboilingwaterbathandtheproductturns(

).ApurpleBgreenC

blueDyellow第9题Diphenylaminecolorimetricmethodcould

beusedtoidentify(

).ADNABRNACallnucleicacidsDbases7.Homework第1题Orcinolmethod

forRNAquantificationisbasedontheconversionof____intheRNAmoleculetoα-furanformaldehydeunderstrongacidconditions.α-furanformaldehydecanspecificallyreactwithorcinol,showinggreencolor.正确答案：:ribose第2题WhichofthefollowingoperationofyeastRNAextractionisincorrect?(

)AExtractionwithNaOHsolutionmustbeperformedat4°CtoensurethebiologicalactivityofRNA.BAftercentrifugation,carefullyaspiratethesupernatantwithadropper,anddonotsuckthelowercelldebris.Ifthesupernatantisstillturbid,centrifugeagain.CWhenwashingcrudeRNA,becarefulnottosplashwater.Otherwise,theproductwillbeverystickyanddifficulttobecollected.DOrcinolsolutionispreparedwithconcentratedhydrochloricacid.Therelatedoperationsmustbeperformedinafumehood.第3题RNAmoleculeiscomposedofphosphoricacid,deoxyriboseandbase.(

)第4题Yeast(Saccharomyce),oneoftheprokaryoticmodels,iscommonlyappliedingenecloningexperiment.(

)第5题Which

of

thefollowingstatementiswrong?

(

)ATheRNAextractedbythedilutealkalimethodisdenatured,whichcanbeusedforRNAcomponentidentificationandsinglenucleotidepreparation.However,itcannotbeusedtomeasurethebiologicalactivityofRNA.BAllpentosescould

reactwithorcinol,soorcinoltestcannotbeusedasthebasisforRNAandDNAidentification.CInadditiontodirectlyprecipitatingRNAwithethanol,RNAcanalsobeprecipitatedbyadjustingthepHofthesolutionto4-4.5,

theisoelectricpointofRNA.DTheboilingwaterbathunderdilutealkaline

istolyse

theyeastcellsandreleaseRNA.正确答案：BC第6题InextractingyeastRNAextractionandorcinolquantification,which

of

thefollowingoperationsare

correct?

(

)AThe

extracting

shouldbeconducted

at4℃.BAfterextractionofRNA,adjusttheextractionsolutiontopH5-6withaceticacid.CRNAsuspensionissuctionfiltered.

Thefilterresidueiswashedtwicewith95%ethanolandtwicewithanhydrousetherinsequence.DBecausehydrochloricacidisvolatile,orcinolreagentshouldbeadded

inafumehood.正确答案：BCD第7题Whichofthefollowingmethodscan

be

used

toquantifyRNA?(

)APhosphorusdeterminationmethodBCarbohydratedeterminationmethodCDiphenylaminemethodDSDSelectrophoresismethod正确答案：AB第8题ToquantifyRNAbyorcinolcolorimetricmethod,theabsorbanceshouldbemeasuredat(

).A280nmB620nmC595nmD670nm7.Homework第1题SDSisananionicsurfactant,whichhelpsbacterialyseandkeeptheproteinmaintaininganaturalactivity.(

)第2题____istheindependentgeneticfactoroutofchromosomeinbacterial.

Itcouldself-replicateautonomouslyandstablyinheritcertaintraitsofbacteria.正确答案：:Plasmid第3题Naturalplasmidsarecircularsingle-strandedDNA.(

)第4题Inthefinalstepofplasmidextraction,addthe

eluenttothecenteroftheadsorptioncolumn,andleaveitatroomtemperaturefor2minutestofullydissolvetheplasmidDNAwhich

has

been

adsorbedby

thecolumn.(

)第5题Inthe

presentexperiment,the

forefrontbandat

about100bpobserved

underultravioletlightis____.正确答案：:ResidualRNA第6题TheroleofDuReddyeinagarosegelelectrophoresisis(

).AParticipateintheformationofporestructureBPre-stainthe

gel.Therefore,theplasmidDNAcould

emit

fluorescenceat

300nm,whichiseasily

observedCDenatureplasmidDNADIndicatethe

positionofforefrontbandin

electrophoresis第7题Accordingtothehydrolyticcharacteristics,

catalyticconditionsandmodificationcapacity,restrictionenzymescould

bedividedinto(

).ATypeIBTypeIICTypeIIIDTypeIV正确答案：ABC第8题Inthisexperiment,iftheunexpectedresultsare

shown

afteragarosegelelectrophoresis,thepossiblereasons

are

().AThepurityoftheplasmidDNAislowandtheimpurityproteinsarenotremovedcompletelyBImproperselectionofreactionbuffersystemCTheamountofenzymeanddigestiontimeareinappropriateDAlltheaboveanswersarecorrect正确答案：ABCD第9题Thereagent

of

thefirststepinthealkalinelysismethodoftencontainsEDTA.Itsfunctionisto(

).AhelatingmagnesiumandcalciumionstoinhibitDNaseactivityBpromotingRNAhydrolysisClysingbacteriaDadjustingpH7.Homework第1题Whataretherolesof25%sulfuricacidintheexperiment?(

)ADenature

enzymetostoptheenzymaticreaction.BProvidetheacidicenvironmentrequiredforKMnO₄titr